I have reconstructed a digital panel meter from LCD to led. But it will not
read any voltage, shorting the input it registers 00.0 and alternates mines
on and off. input open it displays the dp and the one. Can any one give me
any suggestions as to what is wrong.

Thank you in advance A. Brown

 

I have reconstructed a digital panel meter from LCD to led. But it will not
read any voltage, shorting the input it registers 00.0 and alternates mines
on and off. input open it displays the dp and the one. Can any one give me
any suggestions as to what is wrong.

Thank you in advance A. Brown

Sounds like an over range. On those IC's, they were 200mV full scale as I recall (?). Measure the voltages and see what the meter inputs are getting.

 

From the data sheet, the ICL7107 is designed to run LED displays. If you were using an ICL7106 made to use LCD, then that might explain the problem.

Otherwise, can you post up the schematic for the complete meter?